1. Field of the Invention
The invention relates to a housing that is capable of connecting a container and a medical device. The medical device can comprise, for example, a syringe, an infusion set, or the like. The container can comprise a bag, a vial, a tube, or other container.
2. Discussion of the Art
Many pharmaceutical products are delivered to pharmacies in sealed containers such as glass or plastic vials, glass or plastic bottles, and flexible bags. Such containers can contain a powdered or lyophilized formulation of a pharmaceutical product that must be reconstituted with an aqueous diluent prior to administration to a patient. In addition, such containers can contain a solution or suspension formulation of a pharmaceutical product that can be withdrawn from the container and administered directly to a patient, for example, by parenteral administration.
Most pharmaceutical vials are sealed by a pierceable stopper that is press-fit into the mouth of a vial to thereby isolate the contents of the vial from the external environment of the vial. In order to access the pharmaceutical product within the vial, it is necessary either to pierce the stopper or remove the stopper from the vial. A conventional syringe can be used to add a diluent to the vial and/or to withdraw liquid from the vial. The syringe has a hollow needle that is pushed through the stopper and into communication with the contents of the vial. The plunger of the syringe can be depressed to dispense a diluent into the vial or pulled outwardly to draw liquid from the vial into the syringe.
The piercing of stoppers of vials typically has been achieved through the use of sharp, small-bored needles. Standard hypodermic syringe needles are particularly useful for this purpose because they allow the pharmaceutical product to be aseptically withdrawn from the vial and parenterally administered to a patient using a single device, thereby minimizing risk of contamination of the pharmaceutical product. In this mode, needles are typically connected to the syringe by means of a Luer-lock fitting. Luer-lock fittings are known to those skilled in the art. Such a fitting has been used in medical applications for joining an injection needle to a syringe, to link catheters, to link infusion sets, and to provide fluid communication for aqueous solutions of medicaments in a variety of settings. Typically, the Luer-lock fitting has a taper that matches the taper of the interior wall portion of the opening of the device into which it is inserted. Force is used to introduce the Luer-lock fitting into the opening of the device, and the matched tapers provide a substantially leak-proof seal.
The tapered structure of the Luer-lock fitting is subject to well-known and understood mechanical standards. Luer-lock fittings can be made of glass or metal, but are typically made of thermoplastic materials, such as, for example, polycarbonate, polypropylene, polystyrene, polyvinyl chloride, and the like. The experience of the industry has been that the Luer-lock fitting has great value, but is not free of operating problems. Conventionally, Luer-lock fittings are made from rigid thermoplastic materials, which provide little flexibility in the seal region and limit the depth that the male member of the Luer-lock fitting can be inserted into the receiving member of the Luer-lock fitting.
Examples of conventional tapered fittings are shown in Dennehey et al., U.S. Pat. No. 4,439,188 and Dalton, U.S. Pat. No. 5,312,377. The surfaces of the tapered male member of the fitting and the tapered female member of the fitting have a matched taper in these fittings. In these conventional designs, it is required that the taper of the mating surfaces of the tapered male member of the fitting and the tapered female member of the fitting be closely matched and come in close contact to make a satisfactory seal. Slight errors in the manufacturing of these tapered members typically result in a seal that either cannot be initially achieved or subsequently maintained.
Any moment of force normal to the line of contact of the male member of the fitting and the female member of the fitting can result in failure of the seal. There is a need for a device that can compensate for Luer-lock fittings that deviate dimensionally from current industry standards, yet still provide a satisfactory seal. There is also a need to reduce the amount of force or effort required by the user to insert the male member of a Luer-lock fitting into the opening of the female member of the Luer-lock fitting. It is also desired that the seal effected between the male member of the Luer-lock fitting and the female member of the Luer-lock fitting provide a positive sense of engagement, or xe2x80x9cfeelxe2x80x9d to the user, in order to confirm that the male member of the Luer-lock fitting and the female member of the Luer-lock fitting are fully engaged, i. e., that the seal has been formed in such a manner that it will survive expected use and remain engaged even when subjected to a moment of force normal to the line of contact of the male member of the Luer-lock fitting and the female member of the Luer-lock fitting.
In one aspect, this invention provides a housing that can be used to form and maintain a fluid-tight connection between a container and a medical device. The housing comprises an internal receiving surface circumscribing a cavity into which a fitting of the medical device can be inserted. The internal receiving surface comprises a first wall portion having a first contact annulus and a second wall portion having a second contact annulus. Upon insertion of the fitting into an opening in the cavity of the housing, the fitting forms a primary seal with the first contact annulus and a secondary seal with the second contact annulus. The primary seal is formed as the surface of the fitting contacts the first contact annulus of the internal receiving surface of the housing. A hoop stress caused by the contact between the fitting and the first contact annulus produces a strain in the wall portion of the housing adjacent to the first contact annulus. This strain allows the diameter of the first contact annulus to expand. As the fitting continues to advance in the cavity, the first contact annulus eventually expands to a sufficient diameter to allow the fitting to contact the second contact annulus. The secondary seal is formed as the surface of the fitting contacts the second contact annulus of the internal receiving surface of the housing.
The housing uses a relatively flexible receiving surface in conjunction with a relatively rigid fitting of a medical device to form a reliable fluid-tight connection. Neither the interior of the housing nor the fitting require either precisely matched tapered surfaces or precise machining. The housing provides retention of the medical device by providing frictional contact between the first contact annulus of the internal receiving surface of the housing and the fitting and frictional contact between the second contact annulus of the internal receiving surface of the housing and the fitting. The application of only a relatively low force is needed to form the primary and the secondary seals, and the seals thus formed will provide to the user a positive sense of engagement that indicates to the user that a durable, fluid-tight connection has been formed.
In another aspect, the housing of the invention can be used to establish a fluid-tight connection between a fitting, e.g., a Luer-lock fitting, of a medical device, e.g., a syringe, and a stopper disposed in a container, e.g., a vial. The connection results from the interaction between the fitting and the housing, which is disposed over the stopper in the container. The housing has an internal receiving surface surrounding a cavity into which the fitting is inserted. The internal receiving surface of the housing comprises a first wall portion having a first contact annulus and a second wall portion having a second contact annulus, which annuli provide two seals, a primary seal at the first contact annulus and a secondary seal at the second contact annulus. The seals are formed in the same manner as described previously. The housing can be used in conjunction with a penetrator device that is disposed within the cavity of the housing, which is disposed over the stopper. As the fitting is introduced into the opening in the cavity of the housing, the fitting can cause the penetrator device to move towards the stopper and pierce the stopper by means of a pointed end on the penetrator device, thereby forming an opening in the stopper. Once the stopper is penetrated, then fluid can be withdrawn from the container by means of the medical device, such as, for example, a syringe.
The housing of this invention provides a reliable fluid-tight connection between a container and a medical device. The fluid-tight connection results from the primary seal that is formed by the contact between the exterior surface of the fitting and the first contact annulus of the internal receiving surface of the housing and the secondary seal that is formed by the contact between the exterior surface of the fitting and the second contact annulus of the internal receiving surface of the housing. As a result of the force generated in placing the fitting into the housing, the primary and secondary seals are formed quickly, creating a reliable seal with minimal insertion force.
The fitting can be inserted into the cavity of the housing with relatively low force to provide high frictional retention forces. Such an insertion preferably requires less than a full turn of the fitting to provide a satisfactory fluid-tight seal.
The invention facilitates rapid and safe access to the contents stored within a sealed container. The invention is especially suitable for use with a container such as a glass or plastic vial containing a pharmaceutical product or medicament. However, it will be appreciated that other applications of the present invention are feasible, including, but not limited, applications in connection with parenteral tube sets. The pharmaceutical product may be in liquid form, e.g., a solution or suspension of the product, or in a solid form, e.g., a powdered or lyophilized form of the product. The invention is especially useful with a conventional vial, which is normally sealed with a rubber stopper, which, in turn, is to be pierced by the hollow needle of a hypodermic syringe. When the stopper is pierced, the contents of the vial can be diluted or reconstituted with the contents of the syringe. Alternatively, the contents of the vial can be withdrawn into the syringe for subsequent discharge into another container system or for administration to a patient.